Digital LDR Photosensitive Light Sensor Module

Product Description The Digital LDR Photosensitive Light Sensor Module is a high-sensitivity light detection board designed to measure ambient light intensity and trigger automated systems. It features a 5mm Light Dependent Resistor (LDR) paired with a high-precision LM393 comparator IC for stable signal processing. This dual-output module provides a real-time analog signal for measuring precise brightness levels and a digital output that toggles when light crosses a user-defined threshold. It is a fundamental component for building smart street lights, solar tracking systems, and automated indoor lighting controllers. The module's integrated voltage regulation ensures it works seamlessly with 3.3V and 5V microcontrollers like Arduino, ESP32, and STM32.

Key Features

• Dual Signal Output: Provides both Analog (AO) for precise light measurement and Digital (DO) for threshold-based switching.

• On-board Threshold Tuning: Features a multi-turn potentiometer to set the exact light level at which the digital output triggers.

• High-Precision Comparator: Utilizes the LM393 IC to ensure clean digital transitions and high noise immunity.

• Visual Status Feedback: Includes a power indicator LED and a digital signal status LED for instant debugging and calibration.

• Compact and Easy to Mount: Small PCB footprint with a dedicated M3 mounting hole for secure attachment to project chassis.

Technical Details

• Light Sensitive Element: Uses a premium cadmium sulfide (CdS) 5mm LDR with a spectral peak similar to the human eye.

• Comparator Circuitry: The LM393 dual comparator ensures sharp digital edges (TTL level) with a driving capability of over 15mA.

• Operating Voltage Range: Highly versatile operation from 3.3V to 5V, allowing for direct connection to almost any development board.

• Digital Logic State: Default state is HIGH in darkness and pulls to LOW when light exceeds the set threshold.

• Analog Resolution: The AO pin outputs a voltage proportional to the light intensity, which can be read by a 10-bit or 12-bit ADC.

• Ambient Light Rejection: The integrated circuitry helps filter out high-frequency flickering from some AC lighting sources.

• Spectral Sensitivity: Optimized for the visible light spectrum (400nm to 700nm), making it ideal for day/night sensing.

• PCB Build Quality: Professional-grade FR-4 glass epoxy board with high-quality tin-plated solder pads for durability.

• Current Efficiency: Draws minimal power during operation, suitable for continuous environmental monitoring in IoT devices.

• Potentiometer Precision: Features a high-quality trimmer for fine-grained sensitivity adjustments in varied lighting conditions.

• Signal Integrity: Designed with short trace paths between the LDR and the comparator to prevent electromagnetic interference.

• Interface Pins: Standard 4-pin breakout: VCC (+5V), GND (Ground), DO (Digital Out), and AO (Analog Out).

• Thermal Stability: Maintained performance over an industrial temperature range of -20°C to +85°C.

• Mounting Stability: Includes an integrated M3 screw hole for vibration-proof mounting in robotic or automotive projects.

• Packaging Protection: Solid-state components ensure resistance to mechanical shocks and long-term environmental exposure.